I realised that I had not really done an update on progress. So where are we?

The insulating of the walls were completed week before last and since then the flooring has gone down on the first floor and the garage lined with ply to help seal it, provide some of the fire resistance and something to screw to. The flooring (as with everything) took longer on the steel frame. The joists do not fall on 600mm centres exactly so where the join was off the joist a gusset had to be glued and screwed in. We also glued the floor down with copious amounts of D4 so that will never move! The screws were Timco 50mm Self drilling but they really did not like going through the Egger 22mm chipboard so the needed a pilot hole (another process).

So with the windows on site, wind and water tight is in sight. The first windows went in today and I must say, after much work on getting the detailing right, I think we have come up with a great solution that really minimises the thermal bridges.

I am using a number of products from Soudal to try and make the windows as air-tight as possible and I will blog more on that another time.

So the detail is that the windows have a plywood box round the frame, sealed using Soudal Vapourseal. The ply is Malayan WBP EN636/3. The specification for ply has changed so just asking for ‘External Ply’ is just not good enough. This assembly is then slotted into the frame and pushed through so the 6mm Masterboard can be attached on the outside of the ply so it sticks out by about 20mm. The Masterboard is there at the insistence of the BCO for fire protection. If I had known about that before, I would have made the openings bigger to allow for it. The assembly is then slid back so that the window sits about 20mm back from the front edge of the insulation. The frame is then screwed to the steel opening using 50mm self drilling screws.

When the blockwork is built it will be returned back to close the cavity and the gap between the window frame and the blockwork will be filed with expanding foam tape.

The Soudal Vapourseal is gunned around the frame (2 Beads)

The Ply is screwed to the frame in line with the outside edge

Vapourseal under the frame as there is not enough room for the FlexiFoam

The bottom corner detail showing the Masterboard coming to the edge of the insulation and the ply and window set back

The top corner

2 Beads of Soudal Vapourseal

Fixing the Ply to the frame

The Ply surround complete.

Vapourseal under the frame as there is not enough room for the FlexiFoam

Bottom corner of the window outside showing the masterboard to the edge of the insulation and the ply set back.

The bottom corner detail showing the Masterboard coming to the edge of the insulation and the ply and window set back

A long time ago I came across the Nu-Lok roofing system. One of the issues was that I could not slate the roof in a traditional way as the sarking layer would pose a major design issue in terms of ventilation, strength etc so in looking for a clip in slate system like the French use, I came across Nu-Lok.

I was also not keen on ‘imitation slate’ as my experiences of this have been very poor. Nu-Lok do a ceramic slate that is to all intents a tile that is the same as the tiles you put on a floor or wall. They are a great imitation of slate and generally cheaper than real slate. Planning were happy with them but when it came to getting them installed, Nu-Sustainable had run out. The offer was therefore, for a real slate roof at the same price as the ceramic. In all honesty, I had mixed emotions on this but decided to take the offer.

The ceramic tiles do have an advantage that they are virtually impossible to break and will last for ever (literally!). Interestingly the team who are fitting the roof prefer them!

The problem then was they did not have enough steel batten either! They eventually started the roof on the 6th Nov (2 and a bit weeks later than planned). I had arranged for the tiles to be delivered using transport with one of the small Moffett fork-lift trucks that attach themselves to the back of the lorry as I do not have any Mechanical Off Load (MOL) on site. As it happens the number of pallets was far less than I expected and could possibly have been done by HIAB, but never mind.

Roof has gone on well. Only real issue was that I had got Velux Flashings for a tiled roof and not a slate roof. They do seem to be OK though (Phew!). Well that was the only issue right up until they discovered on Friday that they did not have enough slate!

I think this fascia detail is my favourite. It took a while to work out how to finish the counter battens and provide the leveling to bring the membrane to the level of the fascia and provide a batten for the steel tile batten to be fixed to against the fascia (a unique feature of this system).

Secret Gutter

The last photo is one of the most interesting as the method they use is different to the manual but is better. They also do not use a preformed hip soaker, but a piece of DPC that is cut to shape then bedded on some silicone on the last full length metal tile soaker. It seems to be effective but it remains to be seen long term!

Having completed the roof, just the walls to do! We had a major design issue with the walls and getting a solution acceptable to Building Control to meet the Scottish regulation relating to fire propagation in a cavity. The BCO decided the cavity was everything including insulation through to the steel frame so we came up with a solution using Promat SupaLux. As ever this added to the cost but it cannot be helped as that is what they want. What I fail to understand is why there is not a standard detail for this. A Light Steel Frame is not that new a system. It is in the NHBC Handbook!

So to the detail;

There has to be a vertical and a horizontal break. The vertical is fixed to the inside of a stud; the horizontal is fixed to a piece of right angle bar originally supplied for the roof.

In the last picture you can also see the insulation fixed to the ends of the steel rafter panels. This fitted in quite nicely but as the overhang is not huge, the depth of this is limited to 90mm. Will be interesting to see if it is a hotspot if I ever get an TI camera on the place.

Well the roof insulation is complete at last. Seems to have taken ages; in fact it has at about 5 weeks! Way over what I estimated. Still it is done now and looks really good. The rest of the Velux windows need to go in, but we will leave these until the roof tiles appear just to check the battens are right.